Hybrid quantum networks with atomic memories and quantum dot single-photon sources

Context. This project aims at combining the high purity and large bandwidth of quantum dot single photons with the high efficiency and long storage times of atomic quantum memories into a hybrid quantum network architecture with advantageous properties. We already demonstrated that GaAs/AlGaAs quantum dots can emit transform-limited single photons tuned into resonance with rubidium atoms [1] and that the temporal waveform of these photons can be controlled [2]. In parallel, we realized a rubidium atomic quantum memory with a bandwidth of 660 MHz operating on the single-photon level [3]. The goal of this project is to interface the two systems through an optical fiber link that was recently installed in Basel. Several improvements will be implemented to achieve low-noise operation: controlling the charge state of the dot and enhancing the photon collection efficiency with an optical cavity, as well as controlling the spin state of the atoms to suppress four-wave mixing noise by selection rules. After demonstrating storage and retrieval of quantum dot single photons in the atomic memory, we intend to perform basic quantum networking tasks such as entangling two remote atomic memories [4].

[1] J.-P. Jahn, M. Munsch, L. Béguin, A. V. Kuhlmann, M. Renggli, Y. Huo, F. Ding, R. Trotta, M. Reindl, O. G. Schmidt, A. Rastelli, P. Treutlein, and R. J. Warburton, Phys. Rev. B 92, 245439 (2015). [2] L. Béguin, J.-P. Jahn, J. Wolters, M. Reindl, Y. Huo, R. Trotta, A. Rastelli, F. Ding, O. G. Schmidt, P. Treutlein, and R. J. Warburton, Phys. Rev. B 97, 205304 (2018). [3] J. Wolters, G. Buser, A. Horsley, L. Béguin, A. Jöckel, J.-P. Jahn, R. J. Warburton, and P. Treutlein, Phys. Rev. Lett. 119, 060502 (2017). [4] N. Sangouard, C. Simon, J. Minář, H. Zbinden, H. De Riedmatten, and N. Gisin, Phys. Rev. A 76, 050301 (2007)

Supervisor: Prof. Philipp Treutlein

Eligibility criteria and requirements
We are looking for a highly motivated and experimentally talented PhD student to join our group at the University of Basel in Switzerland. You should hold a master’s degree in physics (or equivalent) and ideally have prior experience in quantum optics or atomic physics experiments. You will work in an international team of 2-4 people on a cutting edge experimental setup. Our group is part of the Swiss national research center in Quantum Science and Technology (QSIT), the Swiss Nanoscience Institute (SNI), as well as several European projects (ERC, Quantum Flagship).

QUSTEC programme follows MSCA eligibility criteria: Required level of experience is ‘Early Stage Researcher’ according to the definition in the work programme of the 2018-2020 Marie Skłodowska-Curie actions: Applicants must, at the date of the respective call deadline of QUSTEC, be in the first four years (full-time equivalent research experience) of their research careers and have not yet been awarded a doctoral degree. Mobility criterion: The applicants must not have resided or carried out their main activity (work, studies, etc.) in the country of the future host organisation for more than 12 months in the 3 years immediately before the call deadline of QUSTEC. Short stays such as holidays are not taken into account. For refugees under the Geneva Convention, the refugee procedure (i.e. before refugee status is conferred) will not be counted as a period of residence/activity in the country of the host organisation.

Application procedure:
The proposed PhD position is part of the QUSTEC doctoral programme, funded by the MSCA-COFUND scheme, coordinated by Eucor – The European Campus, and implemented by Eucor partner institutions (University of Basel, University of Freiburg, University of Strasbourg and the Karlsruhe Institute of Technology), which are joined by IBM-Research in Zurich, and WMI in Munich. The complete description of the programme as well as the full list of research topics can be found on the project website. Candidates are encouraged to indicate two additional research topics that they are interested in, in addition to the selected PhD offer, from the list of available topics that can be found on the programme website.
Please, submit your application exclusively via an electronic submission system.
The deadline for applications is September 30, 2020 at 17.00 (Brussels time)

Before submitting the application, please contact the scientific supervisors (obligatory). For any other issues, please address your request to the programme coordinator (contact details can be found in the Guide for applicants).

Working conditions: All PhD candidates will be employed under a 4-years full-time PhD contract following the national regulations.